(1) Field of the Invention
The present invention relates to a gas circuit breaker and, more particularly, to a gas circuit breaker having an operating mechanism reduced in weight and capable of operating with stability even at a low temperature.
(2) Description of Related Art
As a device for operating a gas circuit breaker, a pneumatic operating device capable of obtaining operating force using pneumatic pressure, a hydraulic operating device capable of obtaining operating force using hydraulic pressure and a spring operation device capable of obtaining operating force by releasing a compressive force of a spring, i.e., an elastic member are ordinarily used.
JP-B-3823676 discloses an example of a gas circuit breaker using a spring as a drive source. This gas circuit breaker has a bearing for supporting a cam shaft and a main shaft, the bearing being provided in an operating device bracket. JP-B-3823676 shows that attachment of movable parts including a cam and a main lever outside the bracket facilitates access from the outside for inspection, replacement or the like.
As another example of a gas circuit breaker, JP-A-2003-199220 discloses a gas circuit breaker having an operating mechanism housed in an operating box 106. In ordinary cases, a gas circuit breaker has an electric heater provided in a lower section of an operating box in order to prevent freezing of instruments in the operating box in the winter.